The present invention relates to a method for detecting antibodies directed against Human Immunodeficiency Virus which can be used for diagnosing AIDS and related diseases, and identifying latent, asymptomatic carriers of such infections.
Acquired Immune Deficiency Syndrome (AIDS) was initially recognized and reported in 1981. Since that time, clinical and epidemiological data have revealed that the incidence of AIDS has reached epidemic levels throughout the world. The causative agent of AIDS has been identified as an RNA retrovirus, the Human T-Cell Leukemia Virus Type III (HTLV-III), also known as Lymphadenopathy Associated Virus (LAV) and AIDS-associated retrovirus (ARV) and recently renamed Human Immunodeficiency Virus (HIV). AIDS patients may suffer from a broad spectrum of opportunistic infections such as Pneumocystis carinii, Candida albicans, herpes simplex virus and cytomegalovirus, and are also frequently afflicted with certain tumors, especially Kaposi's Sarcoma. It has been estimated that the number of patients with AIDS in the United States continues to double approximately every twelve months.
The putative AIDS virus, HIV, has been isolated from peripheral blood mononuclear cells, cerebrospinal fluid, semen, neural tissue, saliva, tears and rarely, urine. In order to determine the prevalence of HIV in the general population, it has been suggested that mass screenings of the population for the presence of antibodies directed against the AIDS virus be undertaken. However, since antibody substances are generally found only in human blood and serum, the proposed screening techniques involve obtaining a blood or serum sample from the patient who is to be screened.
A variety of serological tests have been developed to detect the presence of antibodies to HIV (indicative of exposure to HIV) in the blood of patients with AIDS, AIDS-Related Complex (ARC) and healthy (i.e. asymptomatic) virus carriers. FDA-approved ELISA (enzyme-linked immunosorbent assay), as well as experimental Western Blot kits for the measurement of antibodies against HIV are now available. These include recent (but still experimental) ELISA assay kits that detect specific antibodies directed against the viral envelope protein (gp41 or ENV) and a viral core protein (p24 or CORE) as well as kits utilizing Western Blot technology for detecting the major antigenic proteins of HIV. In addition, methods have been recently developed for detecting these viral antigens in tissue culture fluids of HIV-infected cells cultured in vitro as well.
All of the current AIDS detection methods employ invasive procedures to obtain a blood or serum sample to be analyzed for the presence of antibodies to the HIV virus, i.e. the insertion of a hollow needle or other means for withdrawing a fluid sample from a vein, artery or subcutaneous space. These procedures involve some degree of risk to the health care personnel who are involved in collecting and analyzing these samples as Acquired Immune Deficiency Syndrome may possibly be contracted through inadvertent exposure to a syringe or needle that has been employed to obtain a blood or serum sample from a patient that is afflicted with the disease. Moreover, individuals who are presently considered to be at a high risk of contacting AIDS, such as homosexual men and intravenous drug users, and non-high risk individuals who should be screened, often have unfounded fears that they can contract the disease while being tested for it, and therefore avoid exposure to any test procedures which involve withdrawing blood or serum using a needle.
These problems would be overcome by a non-invasive method for screening for antibodies to HIV. Such a method should be suitable for use in mass screenings and avoid the inherent drawbacks of the prior art invasive serological techniques.